1. Field of the Invention
The present invention relates to the manufacture of laminated glasses of glass and/or plastic such as laminated glasses in large sizes, e.g., glasses for automobiles and buildings, and in smaller sizes, such as masks, screens, eyeglasses, etc . . . More specifically, the invention relates to a new adhesive layer used in the manufacture of such laminated glasses. It further relates to laminated glasses comprising said adhesive layer.
2. Background of the Prior Art
The use of a polyurethane layer as an adhesive layer in laminated glasses is well known and is decribed in numerous patent publications. This layer can provide the sole function of adhesion. It can also have a role as an energy absorber.
This adhesive layer can be used to assemble sheets of various glass and/or plastic substances.
For example, French Patent Publication No. 2,398,606 describes the use of a thermoplastic polyurethane layer for the adhesion, with a glass or plastic support, of a self-repairing plastic layer, that is a layer from which local impressions disappear spontaneously after a short period of time, on the order of a few minutes, said speed of disappearance being a function of the type of impression and the temperature of the plastic. At the same time, this layer can be non-lacerating, that is that in the case of breakage of a glass pane, the layer covers the sharp edges of the glass and protects the faces, eyes or other parts of the body of passengers in a vehicle, for example, or further in the case of safety eyeglasses, the protective layer can prevent the sharp edges contacting the eyes.
The assembly of the self-repairing and non-lacerating plastic layer with the support by means of the thermoplastic layer is carried out by means of heat and pressure, for example by subjecting the laminate to an autoclave cycle.
European Patent Publication No. 0,032,329 describes the use of a thermoplastic polyurethane-based adhesive layer containing a blocking agent. Here again, when this layer is used to manufacture laminated glasses, particularly to join the self-repairing, non-lacerating plastic layer to a rigid support, heat and pressure must be used, for example by subjecting the assembly to an autoclave cycle at a temperature greater than 110.degree. C.
In addition, in this prior art, the manufacture of the adhesive layer necessitates the use of heat for the polymerization of the polyurethane.